Characterization of bis-(phenoxy)phosphazene polymers using static secondary ion mass spectrometry

Phosphazene polymers are a class of materials that are finding applications in membrane separations. A series of substituted bis(phenoxy)phosphazene polymers were characterized using static secondary ion mass spectrometry. The anion spectra contained ions which originate from the phosphazene backbone, as well as from the pendant aromatic moieties. The cation spectra also contained ions derived from the pendant moieties, but consisted primarily of ions which arise from adventitious surface contaminants, such as siloxane compounds and hydrocarbons. The backbone-derived ions could be distinguished from the pendant-derived ions on the basis of their response to prolonged primary ion bombardment: the pendant ions decay at rates that are generally two to four times the rates observed for the backbone ions. This observation is interpreted in terms of the pendant moieties being more easily removed during ablation than the backbone ions.